Age calculator
Exact age and days until your next birthday.
Age calculator computes exact age (in years, months, and days) as of any date you choose, plus how many days remain until the next birthday — useful for precise age calculations beyond just "years old".
How to use
- Enter a birth date and an "as of" date (defaults to today).
- Click "Calculate" for exact age and days remaining until the next birthday.
Common use scenarios
- Calculating exact age for an official form or eligibility check.
- Finding out how many days remain until your next birthday.
- Calculating someone's age as of a specific past or future date, not just today.
- Determining a child's precise age in years and months for a developmental milestone.
✓Content & verification reviewed: 2026-08-25
How we verify Age calculator
How to confirm the calculated age and next-birthday countdown are accurate.
"As of" date defaults to today but can be changed
The calculator defaults to computing age as of today, but you can change the "as of" date to calculate age at any past or future point — useful for figuring out how old someone was (or will be) on a specific date, not just their current age.
Next birthday countdown looks forward from the "as of" date
The days-until-next-birthday figure counts forward from whatever "as of" date you've set, not necessarily from today — if you change the as-of date, the countdown recalculates relative to that date.
Leap-year birthdays (Feb 29) use Feb 28 in non-leap years
For someone born on February 29, the next-birthday countdown treats February 28 as the equivalent date in non-leap years, since Feb 29 doesn't exist in those years — worth knowing if you're calculating for a leap-year birthday specifically.
Before you rely on the result
- The birth date is entered correctly.
- The "as of" date matches what you actually want to calculate age relative to (defaults to today).
- You're aware leap-year birthdays use Feb 28 as the equivalent date in non-leap years for the countdown.
- You've double-checked the years/months/days breakdown against your own expectation for a sanity check.
Who this is for
- Anyone needing an exact age calculation for an official form or eligibility check.
- Anyone curious how many days remain until their next birthday.
- People calculating someone's age as of a specific past or future date.
- Parents or caregivers determining a child's precise age for a developmental milestone.
Real-world examples
Checking eligibility for an age-restricted program
Someone needs to confirm they'll be exactly 18 by a specific enrollment date, so they set the "as of" date to that future date to calculate their exact age at that point.
Counting down to a birthday
Someone curious how many days are left until their next birthday uses the calculator with today's date to get an exact countdown.
Calculating a child's precise age for a milestone
A parent needs their child's exact age in years and months for a developmental checkup form, rather than just rounding to the nearest year.
Limitations
- Leap-year birthdays (Feb 29) are treated as falling on Feb 28 in non-leap years for the next-birthday countdown.
Frequently asked questions
Can I calculate age as of a date other than today?
Yes — change the "as of" date field to any past or future date, and the calculator computes age relative to that date instead of today.
How does the next-birthday countdown work if I change the "as of" date?
It recalculates relative to whatever "as of" date is currently set — so if you set a future "as of" date, the countdown shows days from that date to the next birthday after it.
What happens for someone born on February 29?
In non-leap years, the next-birthday countdown treats February 28 as the equivalent date, since February 29 doesn't exist that year.
Does this account for time zones?
Dates are treated as calendar dates without time-of-day or time zone components, so the calculation is based on the dates themselves as entered.
🔒 Runs in your browser — nothing is uploaded. Results are for reference only; see the disclaimer. Last updated: 2026-08-25
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